WEICHAI WP4GNA Assembly/Disassembly Manual Download Page 1

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Assembly & Disassembly Manual

Gas Engine

Model: WP4GNA

WEICHAI AMERICA CORP.

WEICHAI & PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY.COM

GET YOUR WEICHAI & AFTERMARKET SERVICE PARTS AT FLYPARTSGUY.COM

Summary of Contents for WP4GNA

Page 1: ...Assembly Disassembly Manual Gas Engine Model WP4GNA WEICHAI AMERICA CORP WEICHAI PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY COM GET YOUR WEICHAI AFTERMARKET SERVICE PARTS AT FLYPARTSGUY COM...

Page 2: ...e provider that you choose However your engine warranty does not cover damage or failure caused by improper maintenance or repairs Owner s Manual Maintenance Records Storage Use Store this Owner s Man...

Page 3: ...assembly 21 2 9 Cylinder head assembly and disassembly 23 2 10 valve cover assembly and disassembly 27 2 11 Lifting lug assembly and disassembly 28 2 12 CCV system assembly and disassembly 29 2 13 CCV...

Page 4: ...stem 62 6 1 Ignition system assembly and disassembly 62 6 2 Signal generator assembly and disassembly 63 6 3 ECM assembly and disassembly 65 7 Fuel system 66 7 1 Fuel system assembly and disassembly 6...

Page 5: ...ly 79 9 5 Oil strainer assembly and disassembly 80 10 Starting system 82 10 1 Exploded view of starting system 82 11 Alternator 84 11 1 Alternator assembly and disassembly 84 11 2 Exploded view of alt...

Page 6: ...ult in serious injury or death Note Before proceeding with any maintenance or repair operation place a sign clearly stating Maintenance In Progress Do Not Use on the engine starter switch Take the fol...

Page 7: ...Pos Name Pos Name 1 Engine block 13 Fixing plate 25 stud 2 Cylinder liner 14 Welding elbow 26 Cylinder head bolt 3 Camshaft bushing 15 washer 27 Cylinder head bolt 4 Camshaft bushing 16 stud 28 Cylin...

Page 8: ...s key point 2 4 Remove camshaft bushings key point 3 2 1 3 Steps to assemble engine block group Assembling steps are contrary to disassembling ones 2 1 4 Inspection and maintenance of engine block gro...

Page 9: ...done without seal rings Cylinder sleeve for the same engine should be uniform 2 No corrosion scratch and crash damage is allowed for fitting surface and friction surface wipe them out and apply clean...

Page 10: ...and make sure there is no burr overlap and scrap iron Assembly Apply oil on engine block hole put camshaft sleeve into the dedicated tool and guide it into engine block in the meantime align oil galle...

Page 11: ...ng but not limited to Assembly environment must be clean check engine block finished surfaces for crash damage scratch and rust do not bump and scratch the parts during assembling and besides special...

Page 12: ...ock and the others are non thrust bearing caps Take the cap two ends as locating basis when assembling the main bearing bolts cannot be screwed on if the cap is inversely placed WEICHAI PSI SERVICE MA...

Page 13: ...asher 8 baffle 12 breather 2 3 2 Steps to disassemble gear housing group 1 Remove breather 2 Remove plug 3 Remove gear housing key point 1 4 Remove front oil seal key point 2 2 3 3 Steps to assemble g...

Page 14: ...ce as shown in the figure below 2 Apply sealant on the sealing surface of the Gear Housing Ensure that the sealant is evenly distributed and continuous Sealing surface of Gear Housing 3 Place the gear...

Page 15: ...Assembly Oil seals and seal rings should be checked before assembling Ensure there is no damage or dirt For a tight seal apply some clean engine oil on the shaft first and then press the seal in slow...

Page 16: ...ve bolt key point 1 2 Remove bolt key point 2 2 4 3 Steps to assemble nozzle Reverse the disassembly procedure to assemble nozzle 2 4 4 Nozzle inspection and repair Key point 1 Assembly 1 Compress noz...

Page 17: ...Pos Name 1 Thrust plate 2 5 2 Steps to disassemble thrust plate 1 remove main bearing cap 2 remove crankshaft 3 Remove thrust plate key point 1 2 5 3 Steps to assemble thrust plate Reverse disassembl...

Page 18: ...e Pos Name 1 Front cover plate 4 Rear oil seal cap 7 bolt 2 Front oil seal 5 Rear oil seal 3 Engine block 6 washer 2 6 2 Steps to disassemble oil seal 1 Remove gear housing plate 2 Remove front oil se...

Page 19: ...n surface of rear oil seal cover 3 Apply oil on surface of crankshaft flange assemble rear oil seal and tighten bolt Bolt tightening sequence is 1 2 6 7 3 4 5 8 9 10 Key point 2 Inspection Oil seals a...

Page 20: ...llel and level to oil seal cap plane 2 7 Flywheel housing assembly and disassembly 2 7 1 Exploded view of flywheel housing Pos Name Pos Name Pos Name 1 Bolt 6 Bolt 11 Bolt 2 Speed sensor 7 Bolt 12 Pro...

Page 21: ...l is cleaned up Debur the corresponding fitting surface on engine block with 240 fine oil stone and clean the surface with ethyl alcohol Apply sealant on fitting surfaces of flywheel housing and engin...

Page 22: ...isted above the thread and bearing surface of each bolt should be applied with lubricating oil before assembling 2 8 oil pan assembly and disassembly 2 8 1 Exploded view of oil pan WEICHAI PSI SERVICE...

Page 23: ...pan 2 8 2 Steps to disassembly oil pan 1 Remove oil drain bolt 2 Remove fixing bolts 3 Remove oil pan 4 Remove plugs and connectors 2 8 3 Steps to assemble oil pan Reverse disassembly procedure to as...

Page 24: ...lly apply sealant on oil sump place sealing gasket on the fitting surface 2 Lift and place oil sump be careful and avoid crashing the fitting surface 3 Place bolts and gaskets and tighten the bolts wi...

Page 25: ...ntake and exhaust valve module Refer to disassembly of valve mechanism 9 6 for details 5 Remove the valve seal Valve seals can t be reused 2 9 3 Steps to assemble cylinder head 1 Insert the seal valve...

Page 26: ...cylinder head focusing on the combustion chamber surface valve seat intake and exhaust valves and intake and exhaust passages Remove the carbon deposits and mucilage glue and check the surface condit...

Page 27: ...value of valve recession mm Intake valve 1 00 1 45 Exhaust valve 1 00 1 45 2 Clearance between valve rod and valve guide pipe Internal surface of valve guide pipe is the contacting surface between va...

Page 28: ...visible damage and analyze the cause cylinder cover gaskets are disposable and should be replaced during maintenance 2 10 valve cover assembly and disassembly 2 10 1 Exploded view of valve cover Pos...

Page 29: ...install cylinder head cover 4 Install the bolts and fasten The required torque is 10 15Nm 2 10 4 Valve cover inspection and repair Key point 1 Assembly Valve cover gaskets are disposable and should b...

Page 30: ...assembly lifting lug Check the lifting lugs and standoffs for any damaged threads Replace either if damage is found Tighten the lugs after installing them 2 12 CCV system assembly and disassembly 2 12...

Page 31: ...y 5 Loosen the bolts fixing the breather bracket to the engine block Remove the breather bracket 2 12 3 Steps to assemble CCV system 1 Install the breather bracket 2 Install the breather 3 Install all...

Page 32: ...by tool or hand Remove the breather filter element 2 13 3 Steps to assemble CCV breather 1 Clean the inside of the breather Insert a new breather filter element 2 Screw the top cover back onto the bre...

Page 33: ...lley 13 Connecting rod cap 7 Pulley 14 Balance mechanism 3 1 2 Steps to disassemble connect rod mechanism 1 Check before disassembling Check connecting rod axial backlash check tightening torque of co...

Page 34: ...m Reverse disassembly procedure to assemble connect rod mechanism 3 2 Crankshaft group assembly and disassembly 3 2 1 Exploded view of crankshaft group Pos Name Pos Name Pos Name 1 Crankshaft gear 6 P...

Page 35: ...closely fit with cylinder bottom holes 3 Apply clean lubricating oil on inner surface of upper bearing shell 4 Clean up undersurface of cylinder block and make sure there is no grease 5 Apply sealant...

Page 36: ...k and dredge the oil gallery 2 Check the wear condition of crankshaft main journal and neck of crankshaft and check whether there is line like puckering metal peeling and crack 3 Check the wear condit...

Page 37: ...sponding holes on engine block and crankcase do not mix upper and lower shells the one with oil groove is upper one The shell lips should be aligned and applied with engine oil 3 3 4 Inspection and ma...

Page 38: ...re then mark these two gear teeth s crest and flank by marking pen 4 Rotate the gear on the balance mechanism until the gear tooth with 0 marked arrive at the location which is pointed by red circle o...

Page 39: ...Note The gear clearance should be between 0 3mm to 0 4mm Remove balance mechanism and change quantity of adjusting shims on each side if the clearance is less than 0 3mm or greater than 0 4mm replace...

Page 40: ...semble flywheel and gear 3 5 3 Steps to assemble flywheel 1 Fix the flywheel ring gear on flywheel with bolts 2 Knock the pin into crankshaft rear end fully 3 After inserting flywheel guide rod into c...

Page 41: ...g gear is damaged 3 6 Piston rod group assembly and disassembly 3 6 1 Exploded view of piston rod group Pos Name Pos Name Pos Name 1 Piston 6 Piston pin retainer 11 Connecting rod lower bearing 2 Oil...

Page 42: ...nd mark them 3 6 3 Steps to assemble piston rod group 1 Install one circlip into piston circlip groove with internal circlip plier and rotate the circlip to ensure it is properly fitted The end with c...

Page 43: ...flywheel with external force until cylinder 1 6 get to BDC install thrust plates of cylinder 1 and 6 and screw on connecting rod bolts Rod parting surface should face left side of cylinder block i e...

Page 44: ...tom hole connecting rod body and connecting rod small end oil hole Check alloy layer of connecting rod shell for abnormal wear and peeling phenomenon Check wear condition of connecting rod side faces...

Page 45: ...torque vibration damper and crankshaft pulley to the hub with the damper fastening bolts and tighten 4 Torque vibration damper fastening bolts Bolt specification M10 10 9 6 Tightening torque 60 70Nm...

Page 46: ...p 12 Bolt 21 Cylinder head 4 Adjusting bolt 13 Flange 22 Valve spring 5 Top seat of valve spring 14 Bolt 23 Collet 6 Valve spring 15 Bolt 24 Washer 7 Valve spring seat 16 Camshaft gear 25 Washer 8 Exh...

Page 47: ...2 Rotate camshaft until the 1 piston is at the top dead center check fitting bolts for looseness Remove bolts take flange and camshaft gear down 3 Remove camshaft thrust plate fixing bolts take the th...

Page 48: ...up the bolts with lacquer 4 Install gaskets flange washers and hexagon bolts on camshaft threaded end Measure the axial clearance of camshaft which should be 0 1 0 29mm if the clearance is too small c...

Page 49: ...gear Tighten the bolts with torque spanner tightening torque for M10 bolts 85 90Nm tightening torque for M8 bolts 55 60 5Nm seal up the bolts with lacquer after tightening 4 2 4 Inspection and mainten...

Page 50: ...r and intermediate shaft 3 Put the intermediate gear module in the front cover Install the pin shaft 4 Insert the four M10 bolts after installing the washer Torque the bolts to 65 70 Nm 5 Rotate the g...

Page 51: ...ecessary Before installing the tappet it must be cleaned with compressed air Check to ensure that the oil channel is smooth 2 Apply clean lubricating oil evenly onto the engine block tappet fitting ho...

Page 52: ...mooth 3 Ensure that the pushrod is not crooked Check wear condition on the outside surface 4 Ensure that the two ends of the pushrod are not worn 5 Ensure that the valve tappet surface and undersurfac...

Page 53: ...can slide smoothly in valve guide pipe NOTICE Check and ensure spring in valve rod seal cartridge is in good condition before assembling 3 Install valve inner and outer spring 4 Assemble upper valve...

Page 54: ...er seat shaft circlip butterfly spring washer rocker and the other butterfly spring washer Mark the items to prevent improper assembly 4 6 3 Steps to assemble rocker arm and shaft 1 Check whether all...

Page 55: ...in a 0 3mm plug gauge and tighten the nuts with torque spanner to 20 5Nm pull out the gauge make sure the gauge can be easily pulled out and check the clearance with a 0 35mm plug gauge make sure the...

Page 56: ...ame Pos Name Pos Name 1 Air filter 6 Air filter bracket 11 Oxygen sensor 2 Intake pressure reminder 7 Hose 12 Throttle 3 Pipe connector 8 Connecting pipe 13 Flange 4 Connecting pipe 9 Expansion joint...

Page 57: ...re sensor 6 Washer 13 O ring 7 Bolt 14 Gasket 5 1 2 Steps to disassemble air intake and exhaust system 1 Remove air filter fixing bolts loosen clamps to remove air filter and connecting hose 2 Loosen...

Page 58: ...askets down 8 Remove air intake manifold bolts to take air intake manifold and gaskets down 5 1 3 Steps to assemble air intake and exhaust system Reverse disassembly procedure to assemble air intake a...

Page 59: ...of intake manifold bolt is 23N m 5 2 4 Inspection and maintenance of air intake manifold 1 Check the intake manifold for weld defects Replace the pipe if necessary 2 Check the intake pipe gaskets for...

Page 60: ...ifold bolt is 65N m 80N m and do not reuse this bolt more than twice 5 3 4 Inspection and maintenance of exhaust manifold 1 Check for cracks in the exhaust manifold and deformations in the exhaust elb...

Page 61: ...joint 8 O2 sensor 3 Gasket 6 Heat shield 5 4 2 Steps to disassemble exhaust tail pipe 1 Remove nuts and bolts to take expansion joint and gasket down 2 Remove nuts and bolts to take exhaust tail pipe...

Page 62: ...bolt more than twice 5 4 4 Inspection and maintenance of exhaust tail pipe 1 Check for cracks in the exhaust tail pipe and deformations in the expansion joint Replace them if necessary 2 Check the exh...

Page 63: ...ion coil 6 Coil seat 6 1 2 Steps to disassemble ignition coil 1 Remove the fixing bolt to take ignition coil down 2 Remove the fixing bolt to take coil seat down 3 Remove spark plug 6 1 3 Steps to ass...

Page 64: ...ame Pos Name 1 Nut 7 Gear 13 Nut 2 Washer 8 Filling plate 14 washer 3 stud 9 Nut 15 Toothed disc 4 Signal generator 10 Bolt 16 Filling plate 5 Speed sensor 11 Washer 17 Nut 6 Bolt 12 Cover plate 18 WE...

Page 65: ...shaft to OT make sure that the first cylinder piston is in its compression stroke 2 Remove bolt 10 and take the cover plate down 3 Remove nut 3 and washer 14 4 Adjust toothed disc 15 align the TDC lin...

Page 66: ...emove ECM bracket 6 3 3 Steps to disassemble ECM Reverse assembly procedure to assemble ECM 6 3 4 Inspection and maintenance of ECM 1 Check to see if any ECU connection pins are corroded bent broken m...

Page 67: ...T junction 11 Pipe connector 2 LPG evaporator 7 Pipe connector 12 EPR 3 Pipe connector 8 Shut off valve 13 Mixer 4 Shut off valve 9 bracket 14 Mixed air intake connecting pipe 5 Pipe connector 10 Gas...

Page 68: ...Shock pad 17 T junction 6 Washer 12 Bolt 18 Washer 7 2 2 Steps to disassemble LPG evaporator 1 Remove gas connecting hose and clamps to separate LPG supply system and NG supply system 2 Remove bolts a...

Page 69: ...f LPG evaporator 1 Check the LPG gas valve and hoses for leaks 2 Check the coolant fittings and hoses for leaks 7 3 NG shut off valve assembly and disassembly 7 3 1 Exploded view of NG shut off valve...

Page 70: ...of EPR Pos Name Pos Name Pos Name 1 Mixer 3 Bolt 5 Washer 2 EPR 4 Gas pipe 6 Bolt 7 4 2 Steps to disassemble EPR 1 Remove the socket head bolts bolting the gas pipe joint to the EPR take gas pipe dow...

Page 71: ...me No Part Name 1 Screws 6 Diaphragm 11 Spring 2 Mixer Cover 7 Ring 12 Adjustment Screw 3 Spring 8 Air Fuel Regulator Valve 13 Gasket 4 Screws 9 Diaphragm Assembly 5 Board 10 Mixer body WEICHAI PSI SE...

Page 72: ...clockwise to increase the flow of gas 2 Replace the gas diaphragm with a biogas diaphragm to increase the flow of gas To replace the mixer diaphragm according to maintenance specifications 1 Remove t...

Page 73: ...keeping the engine within the normal operating temperature range The cooling system primarily consists of the water pump fan expansion water tank water tank and thermostat No Part Name No Part Name No...

Page 74: ...e fan 1 Prior to assembling check the fan flange and fastening bolts for any manufacturing defects or damage Replace them if necessary 2 Reverse the Disassembly Procedure to assemble the Fan Note do n...

Page 75: ...e bolts on the water pump 4 Remove water pump gasket and filling spacer 8 3 3 Steps to assemble water pump Reverse the Disassembly Procedure to assemble the Water Pump 8 3 4 Water Pump Inspection and...

Page 76: ...e 2 Remove the connecting hose between thermostat and water pump 3 Remove thermostat 8 4 3 Steps to assemble thermostat Reverse disassembly procedure to assemble thermostat 8 4 4 Inspection and mainte...

Page 77: ...d view of lubricating system No Part Name No Part Name No Part Name 1 Oil pump 3 Oil pan 5 Oil filter 2 Oil strainer 4 Oil cooler WEICHAI PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY COM GET YO...

Page 78: ...d damage 2 Clean up the fitting surface between oil pump and engine block 3 Install engine oil pump 4 Install and tighten the two toothed hexagon bolts and self locking nut 9 2 4 Inspection and mainte...

Page 79: ...r 11 Clamp 19 Water inlet pipe 4 Stud 12 Filter 20 Water outlet pipe 5 Nut 13 Bracket 21 Hose 6 Bolt 14 Washer 22 Clamp 7 Oil cooler 15 Washer 23 Bolt 8 Water drain valve 16 Bolt 24 Hollow bolt 9 3 2...

Page 80: ...hem hook up water inlet pipe and outlet pipe and tighten clamps 4 Install and tighten oil filter 9 3 4 Inspection and maintenance of oil filter and cooler 1 Check oil filter for damage replace it if t...

Page 81: ...le on the module 3 Install the valve and tighten it 9 4 4 Inspection and maintenance of pressure limiting valve 1 Check the condition of valve spring replace the spring if necessary 2 Check the valve...

Page 82: ...there is no manufacturing defect and damage Replace new O ring at the same time 2 Clean up the oil supply hole of oil pump and the strainer inner cavity 3 Install the strainer 4 Assemble and tighten t...

Page 83: ...d view of starting system as following No Part Name No Part Name No Part Name 1 Starter 3 Protective cap 2 Bolt 4 Protective cap 10 1 1 Steps to disassemble starting system 1 Fully disconnect all harn...

Page 84: ...heck the starter motor gear for damage replace it if necessary 2 Check the starter wiring to ensure that it is correct tight and secure WEICHAI PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY COM...

Page 85: ...mbly 11 1 1 Exploded view of alternator No Part Name No Part Name No Part Name 1 Bracket 3 Alternator 2 Bolt 4 Belt 11 2 Exploded view of alternator WEICHAI PSI SERVICE MANUALS AVAILABLE ONLINE AT FLY...

Page 86: ...he ground cable and the battery cable from the alternator 3 Remove all bolts bolting the alternator to the bracket Remove the alternator from its bracket 4 Remove the bolts bolting the alternator brac...

Page 87: ...ut of Signal Generator Driving Gear M10 10 9 65 70 65 80 Nuts of Signal Generator Shaft M14 1 5 85 100 85 110 Hexagon bolts and stud of flywheel M12 12 9 140 145 140 170 M10 12 9 80 85 80 95 Bolts of...

Page 88: ...t top ring The second ring 0 06 0 095 Oil ring 0 05 0 085 10 Plane values of valve bottom recess cylinder head 1 0 1 45 11 Plane values of cylinder liner top above the engine body 0 05 0 10 12 Camshaf...

Page 89: ...he outer diameter of the cam base circle 0 05 The outside diameter of crankshaft journal 0 12 0 15 The diameter of connecting rod bearing bore 0 10 The outer diameter of the crankshaft main journal 0...

Page 90: ...America Corp 3100 Golf Road Rolling Meadows IL 60008 http www WeichaiAmerica com WEICHAI PSI SERVICE MANUALS AVAILABLE ONLINE AT FLYPARTSGUY COM GET YOUR WEICHAI AFTERMARKET SERVICE PARTS AT FLYPARTS...

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WEICHAI WP4GNA, Assembly/Disassembly Manual

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